There's joy in the blues — potatoes, that is

Variety, they say, is the spice of life. But novelty can be a little scary, too. In his book, "Molecular Gastronomy," Hervé This points out that the animal kingdom — including humans — "is protected by the phenomenon of neophobia," the fear of what is new. Perhaps this explains the slow approach that the American public has taken in getting acquainted with blue and purple varieties of potatoes.

Of course, blue potatoes aren't really "new" at all. Like all potatoes, they originated thousands of years ago in South America. But unlike some of the more familiar varieties of spuds, these were introduced to North America only in the 1970s. And it's only since the turn of this century that chefs and home cooks have begun to embrace the blues with any real enthusiasm.

Ah, well, it took hundreds of years for Europeans to accept any potatoes as food, so a few decades of hedging around might not be all that significant.

In the Andean highlands where potatoes were first domesticated, they come with skin and flesh in all sorts of colors from red and purple to white and yellow with pigments penetrating to varying degrees from no more than skin deep to ruby red or brilliant blue at the core. What distinguishes the blue varieties from the others is a fairly common bundle of phytochemicals known as the anthocyanins. These are the same pigments that give purple cabbage, pomegranates and blueberries their color. And like the carotenes, another familiar group of phytochemicals, these pigments have antioxidant properties associated with a reduced risk of heart disease and cancer.

Yes, blue potatoes are good for you. But don't let that stop you from enjoying them for purely aesthetic reasons. These spuds are gorgeous.

I like to accentuate the color by serving them with other brightly colored foods. A sky-blue mash makes a fine foundation for a fillet of brilliant red sockeye salmon, dressed in a golden splash of apple-cider butter. When you add the crazy hues of that green cauliflower known as Romanesco, or even a few spears of ordinary broccoli, an everyday meal becomes a psychedelic experience.

Whenever food starts looking a little too white and brown, I like to plate blue potatoes in a kaleidoscopic array with orange carrots, green Brussels sprouts and red and yellow beets to ward off the winter doldrums.

It's this potential for uniqueness that prompts cooks to buy blue potatoes and motivates growers to plant them, says John Thulen of Pioneer Potatoes, a grower whose family has been planting potatoes in the Skagit Valley since the 1880s. "You never know when a store or a distributor is going to want a novelty variety or two in their order," says Thulen, "and if you can fill the need for the novelty varieties, they'll place their entire potato order with you."

So Thulen plants a few acres of blues every year, even though the yields and the demand might be lower than for more standard varieties like Yukon Golds or fingerlings. He typically has shipped all of his potatoes by mid-January, but the potatoes store very well and local stores keep them stocked through March.

In Western Washington, the preferred varieties of blue or purple potatoes are "All Blue" and "Russian Blue." With low moisture and a fairly high starch content, these varieties can be handled like russet potatoes. They bake up fluffy and light, and make a fine purée. They're also good for frying, but if you want to enjoy the color at its most brilliant, avoid browning them. We sometimes see the smaller and darker "Purple Peruvian," which is a little denser and waxier than "All Blue"; it's perfect for steaming whole or cutting up and dressing for salads. Adding a vinegary dressing to these potatoes can make for a very vivid salad indeed.

Anthocyanins are sensitive to pH balance, and acid brings out the red tones, turning the blue a brilliant violet color. All of the blue and purple potatoes can be relied on to make the best batch of mashed potatoes you've ever tasted. If you were blindfolded, you might not be able to tell the difference, but keep your eyes open.

Greg Atkinson is a chef instructor at Seattle Culinary Academy. He can be reached at greg@westcoastcooking.com. Steve Ringman is a Seattle Times staff photographer.

Mashed Blue Potatoes

Makes about 6 cups

Because the potatoes are mashed with the water they were cooked in, no milk is necessary; it would only mask the brilliant color and delicate flavor of these spuds. Using oil instead of butter to enrich the mash allows the delicate flavor of the potatoes to stand out.

3 pounds blue potatoes

1 tablespoon kosher salt

About 6 cups water

6 tablespoons (about 1/3 cup) canola oil

1. Peel the potatoes and cut them into 1-inch cubes. Put the cubed potatoes and the salt in a heavy, 1-gallon stockpot and add just enough water to barely cover them. Cook the potatoes until they are fork tender and just beginning to fall apart, about 15 minutes.

2. Drain the potatoes through a colander over a bowl or another pot to save the cooking liquid. Force the cooked potatoes through a ricer, or, if no ricer is available, put the drained potatoes back in the pot in which they were cooked and mash them with a potato masher or a whisk. Whisk in the oil and just enough of the reserved cooking liquid to render the mashed potatoes smooth and creamy.

3. Covered and placed over the lowest possible heat, the potatoes may be held for up to 20 minutes before serving. If the potatoes are going to be held for more than a few minutes, make a ring of aluminum foil and put it between the burner and the pot. Serve the mashed potatoes hot.